A few weeks ago, I was tidying up my portable hard drive and came across a few photographs that my brother took of a couple of Yellow Cururu Toads (Rhinella icterica) copulating. He'd found them during a trip to the countryside of Sao Paulo, Brazil, at the end of 2011 - towards the end of the species' breeding season.

The R. icterica is an endemic species that can be found in Brazil, eastern Paraguay and the northeastern part of Argentina. It is considered to be a large toad species with males ranging from 100 - 166 mm in length and females ranging from 135 - 190 mm. Due to its sexual dimorphism, it is easy to differentiate males and females of this species - males have a distinct yellow colouration whereas females tend to be a greyish/brownish colour with symmetrical dark spots on either side of their spinal cord.

Female Rhinella icterica | Credit: Caio Biasoli

Male Rhinella icterica | Credit: Caio Biasoli

Similarly to other large toad species such as the Cane Toad (Rhinella marina), the R. Icterica has prominent parotoid glands behind their eyes. These granular glands produce toxic secretions that look like a milky substance if you were to squeeze them. As these toads are not very agile, preferring a 'sit and wait' approach to predation, the toxin secreted is one of their only defence mechanisms. Given their size, it is not surprising to learn that they prey on pretty much anything they can swallow. Having said that, studies indicate that a large portion of their diet may be made up of beetles and ants (Sabagh, Carvalho-e-Silva and Rocha, 2012).

Interestingly, in Brazil, the term 'sapo-cururu' is applied commonly to big toads, mostly of the Rhinella genus. The word 'Cururu' is Old Tupi in origin and used colloquially in some regions to describe an ugly human male. There's also a popular children folklore song named 'sapo-cururu' that makes reference to the loud calls made by the males of the species during the breeding season.